Today's mobile backhaul (MBH) networks/radio access networks are usually structured into two parts, the High-RAN (radio access network) and Low-RAN sections, in order to provide connectivity and traffic aggregation for mobile packet data from cell sites to the core network. As can be seen from FIG. 1 the High-RAN part is typically using a ring topology with the network nodes 20 to 24, while the Low-RAN part is using a tree-structure with the network nodes 31 to 34. The cell sites are connected to the Low-RAN. The Low-RAN is typically using microwave links to the access legs of the High-RAN ring. The head-end of the High-RAN ring connects to the core network using core routers, such as routers 10 and 14 placed on the core site. The edge router connects as well to the core network CN via at least two independent links as shown in FIG. 1.
Furthermore, a split router architecture is known in which a common router is split into two elements, as known inter alia from a ForCES documentation in IETF at http://datatracker.ietf.org/wg/forces/.                a control element (CE) responsible to manage the routing protocol and the connectivity of the data plane. The control element controls the data plane connectivity through the forwarding elements (FE).        the forwarding element responsible to forward traffic in the data plane, the forwarding element establishing the connectivity to neighbor nodes based on instructions received from the control entity.        
Furthermore, data plane applications are known in mobile networks. Examples of data plane applications are policy and enforcement functions, service aware traffic shaping, transcoding, transrating, media caching, packet inspection and media proxies, etc. One example of data plane applications is a packet inspection in which the data packets are inspected to identify malicious data. Another data plane application is the counting of data packets for charging functions.
In FIG. 2 the location of data plane applications as known from the art is shown. In the left side of FIG. 2, the ring structure of the radio access network part is shown, the right side showing the edge router 10 as connection point to the core network to which data plane applications 41 to 43 are attached. The connection of the data plane applications to the edge router as shown in FIG. 2 has the disadvantage that either more interface cards are required on the router or a site LAN switch is required. Furthermore, routing capacity is needed on the router to loop the data plane flow via several data plane applications. Additionally, the handling of separate entities to host the data plane applications is an additional work for the operators of the network.
To improve the situation it is known to move the data plane applications into the edge router as shown in FIG. 3 where the data plane applications 41 to 43 are incorporated into router 10a. However, although this simplifies the site as such, the complexity is moved into the router. The router platform is not prepared to host processing intensive functions and the dimensioning of the router has become a problem. Furthermore, scalability issues come up when the data plane flows to be passed through the data plane applications increase.
Thus, the idea to host multiple data plane applications on the router as shown in FIG. 3 may be a short time solution, but does not scale into the future especially with the predicted increase of packet traffic volume.
The increasing need for multiple data plane applications and increasing mobile packet data traffic causes scalability and cost problems for the edge routers and the data plane applications.